1. Field of the Invention
This invention relates to mechanisms for spacecraft. Particularly, this invention relates to systems and methods for releasing payloads in space.
2. Description of the Related Art
Separating a major mass item payload from a spacecraft presents a unique problem, particularly if the center of gravity of the payload is not aligned to the separating force vector. Eccentricity of the applied force will impart a rotational motion (or tumble) in addition to the desired linear separating motion which could lead to detrimental recontact of the payload and spacecraft. Other factors can also contribute to undesirable payload tumble.
Spacecraft payloads are often released suddenly by multiple devices that suddenly disengage the payload from the spacecraft at many different points. The release devices are typically explosive and can impart additional energy to the payload in an unpredictable manner. In addition, stored energy in the structure and preloaded joints may also contribute to an unpredictable payload release. Sequenced releases of the multiple devices can sometimes alleviate the problems of an unpredictable payload release. However, there are still many factors that can contribute to payload tumble and it is important to have systems and methods for releasing payloads in a controlled and/or predicatable manner.
Any release system for space applications should also possess other important characteristics. The systems and methods should be very reliable as often failure of a system or mechnism in space affords little or no opportunity for recovery or repair. The entire spacecraft may be lost from a single failed mechnism. In addition, minimizing mass is always an important consideration in space applications. Delivering any object into space is an expensive undertaking and costs generally increase in direct relation to the mass of the spacecraft. In addition, if the mass of supporting systems can be reduced, it allows the payload mass to be increased which can directly affect the mission objective. For example, more mass for the payload may enable a higher power antenna system with better performance. In a related manner, smaller size is also a desirable characteristic for space systems. All spacecraft components must fit within the launch vehicle shroud. It is important that systems are designed that are as compact as possible. Finally, cost of the devices themselves is also a consideration in the design and manufacture of any system for space applications.
In view of the foregoing, there is a need in the art for systems and methods for releasing space payloads in a manner that minimizes forces that may induce undesired rotation or tumble to the payload. Further, there is a need for such systems and method to be simple, reliable, light and compact. There is also a need for such systems and methods to be inexpensive to manufacture and test. As detailed hereafter, these and other needs are met by embodiments of the present invention.